Disk-shaped recording media which apply optical recording (hereinafter referred to as “optical disks”), such as a DVD (Digital Versatile Disk) and a CD (Compact Disk), have rapidly become popular for use in storage of computer files or movie streams. Optical disks have a large storage capacity and are randomly accessible. Furthermore, unlike contact-type magnetic recording media, there are no concerns about wearing or damage on a recording surface as a result of reading, head crash, etc. In addition, the disk surface is hard, and the risk of data being accidentally lost is low.
Recording and playback apparatuses using optical disks have already been widely used as, for example, external recording media for computers and external storage apparatuses. Recently, with an increase in the recording capacity of disk-shaped recording media, video cameras of the type that stores a movie on a disk instead of a traditional video recording tape have been appearing (see, for example, Patent Document 1).
Disk-shaped recording media are randomly accessible, and allow efficient searching of a favorite scene. In addition, due to the contactless access to data, recording media can be utilized without deterioration. For example, due to the high image quality or ease of use such as editing capabilities, the number of users of DVD video cameras has been increasing year by year since their sale in 2000.
For example, in the AVCHD (Advanced Video Coding High Definition) standard, specifications regarding data formats for High Definition (HD) video cameras and so forth are being established by adding recording compatibility and additional-recording compatibility functions while appropriately inheriting the content of existing disk format standards. The AVCHD standard adopts the MPEG-4 AVC/H.264 scheme, which provides a high compression ratio, and mainly aims to make it possible to record an HD image on a low-capacity low-speed recording medium. While recording on DVD disks is assumed, it is also possible to perform recording on a variety of recording media such as a memory card and an HDD in accordance with the AVCHD standard format (see, for example, Non-Patent Documents 1 and 2).
In the AVCHD standard, MPEG (Moving Picture Experts Group)-2 System has been set as a movie stream file form, where a multi-file structure in which not only a stream file alone is stored on a recording medium but also a plurality of management information files for playing back or editing a movie file are attached and stored is provided. That is, movie content encoded into an MPEG2-TS stream is such that a collection of data, which is a unit that requires continuous synchronous playback, i.e., playback for which real-time playback is guaranteed, constitutes one clip (Clip) and is recorded as one clip AV stream (ClipAVStream) file. Additionally, when a clip AV stream file is recorded on a recording medium, individual types of management information files called a play list (PlayList) file and a clip information (ClipInformation) file are attached and recorded.
A clip information file is a file which exists paired with a clip AV stream file and in which stream-related information necessary to play back an actual stream is described. In addition, a play list specifies a playback start point (IN point) and a playback end point (OUT point) for each of one or more clips to specify a playback section of movie data and a playback order. With the use of those management information files, video-recording and editing functions can be suitably implemented.
Here, editing of a movie stream recorded on a recording medium includes non-destructive editing that only involves an operation such as repositioning or deleting a part to be referred to on a play list visible from a user but does not involve editing stream data on a recording medium, and destructive editing that entails a change of the part itself on the recording medium.
In view of user convenience, it is preferable that non-destructive editing of a movie stream recorded on a recording medium be available. In the AVCHD standard, in addition to a real play list (Real PlayList) that contains content of an entity (that is, a clip AV stream), a virtual play list (Virtual PlayList) that does not contain content of an entity is defined as a play list attribute. The editing of a real play list involves destructive editing that accompanies editing of the content of an entity. The editing of a virtual play list, on the other hand, involves only replacement of a playback start point and a playback end point for a clip AV file, and can be performed using non-destructive editing that prevents the content of an entity itself from being changed.
In current situations, however, the AVCHD standard has no specific regulations regarding how the management information files in the non-destructive editing process described above are operated. As described above, the AVCHD standard format provides a multi-file structure in which a plurality of management information files for playing back or editing a movie file are attached and stored, and it is necessary to correctly describe the management information files in the non-destructive editing process as well as in the destructive editing process.
For example, when a non-destructive editing operation including copying of the same playback section a plurality of times is performed on a digital video camera user interface compatible with the AVCHD standard, it is necessary to consider a process of updating management information files so as not to interfere with the AVCHD standard.    Patent Document 1: Japanese Unexamined Patent Application Publication No. 2004-120364    Non-Patent Document 1: http://www.avchd-info.org/    Non-Patent Document 2: http://support.d-imaging.sony.co.jp/www/handycam/products/benri/avchd/index.html